Method and apparatus for moving a swing tail cargo door on an aircraft

ABSTRACT

A computer implemented method, apparatus, and computer usable program code for a mobile tail support control system. An apparatus comprises a data processing system, an output device, a set of load sensors, a set of position sensors, and a computer program product executing on the data processing system. The output device is capable of generating signals for managing movement of a mobile tail support apparatus. The set of load sensors may be coupled to the data processing system and may be capable of detecting loads associated with a swing tail cargo door. The set of position sensors are coupled to the data processing system and detect a position of the mobile tail support apparatus relative to the swing tail cargo door. The computer program product may receive information from the set of load sensors and the set of position sensors and generate signals to manage the mobile tail support apparatus.

BACKGROUND INFORMATION

1. Field

The present disclosure relates generally to an improved aircraft and inparticular to a swing tail cargo door on an aircraft. Still moreparticularly, the present disclosure relates to a method and apparatusfor moving a swing tail cargo door on an aircraft.

2. Background

A swing tail aircraft may be an aircraft in which the tail portion ofthe aircraft may be moveably mounted to allow the tail portion to swingor move to expose the inner portion of the aircraft. This tail may alsobe referred to as a swing tail cargo door.

With the use of the swing tail cargo door, larger cargo, such as,without limitation, vehicles, fuselage sections, or wings, may be placedinto and moved out of an aircraft. This type of cargo may be loaded andunloaded from the back of the aircraft with the swing tail in an openposition. In this manner, much larger parts may be placed into theaircraft in comparison to other types of cargo doors.

With large cargo aircraft, the weight of the swing tail cargo door mayrequire aircraft personnel to use equipment to lift or support the swingtail cargo door during movement, loading operations, and unloadingoperations or repositioning of the swing tail cargo door. These types ofprocesses may be manually intensive requiring equipment and personnel tomove and align the swing tail cargo door during repositioning or theopening or closing of a swing tail cargo door.

Currently used systems, however, may not allow for quick closureespecially in high wind conditions. Additionally, currently usedtechniques and equipment may place unnecessary stress on the swing tailcargo door during movement or loading operations and unloadingoperations of the swing tail cargo door. Currently used techniques alsomay add weight to the aircraft if a door control/supportmechanism/system is built into the plane.

Accordingly, there is a need for a method and apparatus forrepositioning a swing tail cargo door, which overcomes the problemsdiscussed above.

SUMMARY

The advantageous embodiments provide a computer implemented method,apparatus, and computer usable program code for a mobile tail supportcontrol system. In an advantageous embodiment, a mobile tail supportcontrol system controls movement of a mobile tail support apparatus. Thecontrol system comprises a data processing system, an output device, aset of load sensors, a set of position sensors, and a computer programproduct executing on a data processing system. The output device iscapable of generating signals for managing movement of a mobile tailsupport apparatus. The set of load sensors are coupled to the dataprocessing system and are capable of detecting a set of loads associatedwith a swing tail cargo door. The set of load sensors comprise a firstload sensor capable of detecting a tangential load of the swing tailcargo door and a second load sensor capable of detecting a vertical loadof the swing tail cargo door. The set of position sensors are coupled tothe data processing system and capable of detecting a position of themobile tail support apparatus relative to the swing tail cargo door. Theset of position sensors comprise a first position sensor capable ofdetecting an angle of the mobile tail support apparatus relative to theswing tail cargo door when the mobile tail support apparatus is coupledto the swing tail cargo door, a second position sensor capable ofdetecting a radial displacement from a fixed distance from a centerlineof a hinge for the swing tail cargo door to a centerline for a ballfitting of the mobile tail support apparatus relative to the swing tailcargo door, and a third position sensor capable of detecting a steeringangle of a wheel on the mobile tail support apparatus. The computerprogram product executing on the data processing system is capable ofreceiving information from the set of load sensors and the set ofposition sensors and is capable of generating signals to manage themobile tail support apparatus. In executing the computer programproduct, the data processing system generates a signal to halt themovement of the mobile tail support apparatus if the radial displacementexceeds a threshold distance and the data processing system generates aset of steering signals based on the angle of the mobile tail supportapparatus relative to the swing tail cargo door and the radialdisplacement in which a set of steering signals are displayed to anoperator of the mobile tail support apparatus or automatically control adirection of travel of the mobile tail support apparatus.

In another advantageous embodiment, computer implemented method isprovided for guiding movement of a mobile tail support apparatus. Radialdisplacement from a coupling radius of the mobile tail support apparatusfrom a swing tail cargo door hinge is received to form a received radialdisplacement. An angle of the mobile tail support apparatus relative tothe swing tail cargo door when the mobile tail support apparatus iscoupled to the swing tail cargo door is received to form a receivedangle. The movement of the mobile tail support apparatus is selectivelychanged based on the received radial displacement and the receivedangle. In selectively changing the movement, a determination is made asto whether continued movement of the mobile tail support apparatus inthe current direction would cause an undesired load on the swing tailcargo door during opening and closing operations. Responsive to adetermination that the mobile tail support apparatus require steeringguidance, guidance is provided to the operator display device bydisplaying a desired direction of the movement for the mobile tailsupport apparatus on a display device, steering signals are sent to asteering unit to change a desired direction of the movement for themobile tail support apparatus, or to stop the movement of the mobiletail support apparatus.

In one advantageous embodiment, an apparatus comprises a data processingsystem, an output device, a set of load sensors, a set of positionsensors, and a computer program product executing on the data processingsystem. The output device may be capable of generating signals formanaging movement of a mobile tail support apparatus. The set of loadsensors may be coupled to the data processing system and may be capableof detecting a set of loads associated with a swing tail cargo door. Theset of position sensors may be coupled to the data processing system andmay be capable of detecting a position of the mobile tail supportapparatus relative to the swing tail cargo door. The computer programproduct executing on the data processing system may be capable ofreceiving information from the set of load sensors and the set ofposition sensors and generate signals to manage the mobile tail supportapparatus.

In another advantageous embodiment, a computer implemented method guidesmovement of a mobile tail support apparatus. A radial displacement ofthe mobile tail support apparatus from a swing tail cargo door may bereceived to form a received radial displacement. An angle of the mobiletail support apparatus may be received relative to the swing tail cargodoor when the mobile tail support apparatus is coupled to the swing tailcargo door to form a received angle. Selectively defining the change inthe movement of the mobile tail support apparatus required, based on thereceived radial displacement and the received angle.

In yet another advantageous embodiment, a computer program productcontains a program code for guiding movement of a mobile tail supportapparatus. The program code receives a radial displacement of the mobiletail support apparatus from a swing tail cargo door to form a receivedradial displacement. The program code receives an angle of the mobiletail support apparatus relative to the swing tail cargo door when themobile tail support apparatus is coupled to the swing tail cargo door toform a received angle. The program code selectively defines the changein the movement of the mobile tail support apparatus required based onthe received radial displacement and the received angle.

The features, functions, and advantages can be achieved independently invarious embodiments of the present disclosure or may be combined in yetother embodiments in which further details can be seen with reference tothe following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the advantageousembodiments are set forth in the appended claims. The advantageousembodiments, however, as well as a preferred mode of use, furtherobjectives and advantages thereof, will best be understood by referenceto the following detailed description of an advantageous embodiment ofthe present disclosure when read in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a flow diagram of aircraft production and service methodologyin which an advantageous embodiment may be implemented;

FIG. 2 is a block diagram of an aircraft in accordance with anadvantageous embodiment;

FIG. 3 is an illustration of a functional block diagram of a mobile tailsupport apparatus for moving a swing tail cargo door on a swing tailaircraft in accordance with an advantageous embodiment;

FIG. 4 is an illustration of an aircraft with a swing tail cargo door inaccordance with an advantageous embodiment;

FIG. 5 is an illustration of an aircraft with a mobile tail supportapparatus in accordance with an advantageous embodiment;

FIG. 6 is an illustration of components in a vertical support system inaccordance with an advantageous embodiment;

FIG. 7 is an illustration of lift structures in a vertical supportsystem is depicted in accordance with an advantageous embodiment;

FIG. 8 is an illustration of lift mechanisms for a vertical supportsystem in accordance with an advantageous embodiment;

FIG. 9 is an illustration of a portion of a vertical support system inaccordance with an advantageous embodiment;

FIG. 10 is an illustration of components used in providing lift forcesin a vertical support system in accordance with an advantageousembodiment;

FIG. 11 is an illustration of a horizontal support system coupled to aswing tail cargo door in accordance with an advantageous embodiment;

FIG. 12 is an illustration of a horizontal support system in accordancewith an advantageous embodiment;

FIG. 13 is an illustration of a swing tail control system in accordancewith an advantageous embodiment;

FIG. 14 is an illustration of a data processing system in accordancewith an advantageous embodiment;

FIG. 15 is an illustration of geometries and parameters for controllinga mobile tail support apparatus in accordance with an advantageousembodiment;

FIG. 16 is an illustration of a steering guidance display in accordancewith an advantageous embodiment;

FIG. 17 is a flowchart of a process for managing movement of a mobiletail support apparatus in accordance with an advantageous embodiment;and

FIG. 18 is a flowchart of a process for monitoring loads on a mobiletail support apparatus in accordance with an advantageous embodiment.

DETAILED DESCRIPTION

Referring more particularly to the drawings, embodiments of thedisclosure may be described in the context of an aircraft manufacturingand service method 100 as shown in FIG. 1 and an aircraft 102 as shownin FIG. 2. During pre-production, exemplary method 100 may includespecification and design 104 of the aircraft 102 and materialprocurement 106. During production, component and subassemblymanufacturing 108 and system integration 110 of the aircraft 102 takesplace. Thereafter, the aircraft 102 may go through certification anddelivery 112 in order to be placed in service 114. While in service by acustomer, the aircraft 102 is scheduled for routine maintenance andservice 116 (which may also include modification, reconfiguration,refurbishment, and so on).

Each of the processes of method 100 may be performed or carried out by asystem integrator, a third party, and/or an operator (e.g., a customer).For the purposes of this description, a system integrator may includewithout limitation any number of aircraft manufacturers and major-systemsubcontractors; a third party may include without limitation any numberof vendors, subcontractors, and suppliers; and an operator may be anairline, leasing company, military entity, service organization, and soon.

As shown in FIG. 2, the aircraft 102 produced by exemplary method 100may include an airframe 118 with a plurality of systems 120 and aninterior 122. Examples of high-level systems 120 include one or more ofa propulsion system 124, an electrical system 126, a hydraulic system126, and an environmental system 130. Any number of other systems may beincluded. Although an aerospace example is shown, the principles of thedisclosure may be applied to other industries, such as the automotiveindustry.

Apparatus and methods embodied herein may be employed during any one ormore of the stages of the production and service method 100. Forexample, components or subassemblies corresponding to production process108 may be fabricated or manufactured in a manner similar to componentsor subassemblies produced while the aircraft 102 is in service. Also,one or more apparatus embodiments, method embodiments, or a combinationthereof may be utilized during the production stages 108 and 110, forexample, by substantially expediting assembly of or reducing the cost ofan aircraft 102. Similarly, one or more of apparatus embodiments, methodembodiments, or a combination thereof may be utilized while the aircraft102 is in service, for example and without limitation, to maintenanceand service 116.

With reference now to FIG. 3, an illustration of a functional blockdiagram of a mobile tail support apparatus for moving a swing tail cargodoor on a swing tail aircraft is depicted in accordance with anadvantageous embodiment. In this example, mobile tail support apparatus300 includes mobile support base 302, vertical support system 304,horizontal support system 306, coupling mechanism 308, and swing tailcontrol system 310. Vertical support system 304 includes lift structure312 and accumulator unit 314. Horizontal support system 306 includescross track slide system 316.

Swing tail control system 310 includes sensors 318 and data processingsystem 320. Sensors 318 include load sensors 322 and position sensors324. Load sensors 322 include vertical load sensor 326 and tangentialload sensor 328. Position sensors 324 include radial travel sensor 330and angle sensor 332. In these examples, load sensors 322 and positionsensors 324 may each be a set of sensors. Also, vertical load sensor326, tangential load sensor 328, radial travel sensor 330, and anglesensor 332 may be a set of sensors. A set as used herein refers to oneor more items. For example, a set of load sensors may be one or moresensors.

Mobile support base 302 may take the form of a vehicle with wheels formoving mobile tail support apparatus 300. Vertical support system 304may be capable of controlling a vertical load of a swing tail cargo doorof a swing tail aircraft. Accumulator unit 314 may be a hydraulic andgas system that provides lift and/or a shock absorber functionality toreduce and/or minimize the vertical movement of the swing tail cargodoor in addition to supporting the swing tail cargo door.

Lift structure 312 may move coupling mechanism 308 into place withrespect to the swing tail cargo door for coupling. Lift structure 312 incombination with accumulator unit 314 may provide vertical support forthe swing tail cargo door when coupling mechanism 308 is coupled to theswing tail cargo door.

Horizontal support system 306 employs cross track slide system 316 toprevent an unacceptable load from occurring on a swing tail cargo dooror hinge of the swing tail cargo door during movement of the swing tailcargo door around an axis through the hinge of the swing tail cargodoor. Loads that occur on the swing tail cargo door may translate intoloads on the hinge or other parts of the swing tail aircraft. Forexample, cross track slide system 316 may eliminate, minimize or reducethe radial displacement of the mobile support base 302 in relation tothe coupling mechanism 308 as mobile support base 302 moves to changethe position of the swing tail cargo door.

In these examples, swing tail control system 310 provides guidance ormanagement of the movement of mobile tail support apparatus 300 duringrepositioning of a swing tail cargo door. Vertical load sensor 326detects the vertical load of the swing tail cargo door on mobile tailsupport apparatus 300 when coupling mechanism 308 is coupled to orengaged with the swing tail cargo door. Tangential load sensor 328detects tangential loads on coupling mechanism 308 of the swing tailcargo door.

In these examples, a tangential load may be a load perpendicular to aline drawn in a horizontal plane from coupling mechanism 308 through thehinge line of the swing tail cargo door. Radial travel sensor 330identifies the amount of change in the travel of mobile tail supportapparatus 300 from the hinge of the swing tail cargo door giving aradial displacement value. In these examples, the coupling radius may bethe distance of coupling mechanism 308 from the hinge of the swing tailcargo door. Radial displacement is the amount of radial displacement theball fitting makes from it's nominal position with respect to the mobiletail support apparatus.

Angle sensor 332 detects an angle of mobile tail support apparatus 300relative to the swing tail cargo door when mobile tail support apparatus300 is coupled to the swing tail cargo door. In these examples, thisangle may be an angle between the centerline of the chassis for mobilesupport base 302 relative to a radial line from coupling mechanism 308to the hinge of the swing tail cargo door. In these examples, anglesensor 332 may be a sensor located at coupling mechanism 308.

Data processing system 320 executes computer program product 334 togenerate output to guide the movement of mobile tail support apparatus300. In response to receiving the radial displacement and the angle ofmobile tail support apparatus 300 from radial travel sensor 330 andangle sensor 332, data processing system 320 selectively generatesguidance to change the movement of mobile tail support apparatus 300.This guidance may be used to manage or control the movement of mobiletail support apparatus 300. This guidance may be, for example, withoutlimitation, steering signals displayed to an operator of mobile tailsupport apparatus 300 on display 336. The presentation of these steeringsignals may cause a selective change in the movement of mobile tailsupport apparatus 300.

The selective change in the movement of mobile tail support apparatus300 may be performed by presenting directions or guidance to an operatorof mobile tail support apparatus 300 through display 336. In otherembodiments, data processing system 320 may generate guidance in a formof signals to steering unit 338 in mobile support base 302 toautomatically change the movement of mobile tail support apparatus 300.These signals also may cause mobile support base 302 to halt movement byengaging a brake system 339 controlled by steering unit 338. Brakesystem 339 includes at least one brake that may be used to slow downand/or stop mobile support apparatus 300.

With reference now to FIG. 4, an illustration of an aircraft with aswing tail cargo door is depicted in accordance with an advantageousembodiment. In this example, aircraft 400 may have wings 402 and 404attached to fuselage 406. Aircraft 400 also may include wing mountedengines 408, 410, 412, and 414.

Aircraft 400 also may have swing tail cargo door 416, shown in both aclosed position and an open position. The open position is shown inphantom in this example. Swing tail cargo door 416 may move horizontallyrelative to the fuselage to change positions. Aircraft 400 may beconsidered to be in an operation configuration in the closed position,allowing aircraft 400 to fly. In these examples, aircraft 400 may beimplemented as a large cargo aircraft for transporting differentcomponents, such as a fuselage and wings of an aircraft beingmanufactured.

With reference now to FIG. 5, an illustration of an aircraft with amobile tail support apparatus is depicted in accordance with anadvantageous embodiment. In this example, swing tail cargo door 416 isdepicted in a closed position on aircraft 400. Swing tail cargo door 416may be opened and closed with assistance from mobile tail supportapparatus 500. Mobile tail support apparatus 500 may be a vehicle havingtool 502, which may be used to move swing tail cargo door 416.

Mobile tail support apparatus 500 may provide vertical support to swingtail cargo door 416 as swing tail cargo door 416 rotates from either anopen to closed position or a closed to open position. Tool 502 may movevertically to engage swing tail cargo door 416 at socket 504 in aircraft400 to open and close swing tail cargo door 416. With tool 502 engagedin socket 504, mobile tail support apparatus 500 may move swing tailcargo door 416 in an arc or path to open and close swing tail cargo door416. Mobile tail support apparatus 500 may provide the force and supportneeded to open and close swing tail cargo door 416 without undesirableforces or stresses being applied to swing tail cargo door 416.

As depicted, tool 502 may include vertical support system 506 andhorizontal support system 508. These components may be mounted on mobilesupport base 510. Mobile support base 510 is an example of mobilesupport base 302 in FIG. 3. Vertical support system 506 may be anexample of vertical support system 304 in FIG. 3, while horizontalsupport system 508 may be an example of horizontal support system 306 inFIG. 3. More detailed illustrations and descriptions of these systemsare provided below.

In these examples, mobile support base 510 may be implemented using anyspecial purpose or standard chassis used for moving and/or liftingitems. One example, without limitation, may be a chassis used for aforklift or some other suitable chassis. A lift truck chassis that maybe used in the different advantageous embodiments may be, for example,without limitation, a Hyster-H 1050HD lift truck, which is availablefrom Hyster Company.

Of course, any chassis suitable for mounting a tool, such as tool 502for moving swing tail cargo door 416, may be used. In selecting achassis for mobile support base 510, the chassis may have sufficientmass to react to various vertical and lateral loads that may be appliedto mobile support base 510 when moving swing tail cargo door 416 indifferent positions. Further, another feature of a chassis may be toprovide smooth and readily controllable slow speed operation, such as,for example, without limitation, 0.5 inches per second to 3.0 inches persecond. Also, mobile support base 510 also may have mounting positionsfor vertical support system 506 and horizontal support system 508 aswell as a location for a controller for these components.

Additionally, brake system 339 in mobile support base 510 may be, forexample, without limitation, hydraulic brakes. Brake system 339 may becoupled to solenoid valve 341 to activate brake system 339 in parallelwith a normal brake pedal. Further, mobile support base 510 also mayprovide a signal to identify the angle of steering wheels 343. Thissignal may be provided through a modification of mobile support base 510to include a sensor to identify the angle of steering wheels 343.

A sensor may be added to the steering actuator 345 to supply theposition of the wheels with respect to a centerline through mobilesupport base 510. Also, mobile support base 510 may provide or may bemodified to include speed sensor 347 with a resolution within a desiredspeed range when moving swing tail cargo door 416. Further, mobilesupport base 510 also may provide an indication of direction of travel,such as, for example and without limitation, forward or reverse.

Gear tooth sensor 349 and gear wheel 351 may be added to drive shaft 353at drive axel 355 to reliably and accurately sense the speed of mobilesupport base 510 during low speed operations. Proportional servo valve357 may be added in parallel to brake system 339 to partially apply thebrake system 339 during travel to control vehicle speed. Further, asignal may be obtained from the transmission control 361 to provide adirection of travel.

In this manner, mobile tail support apparatus 500 may prevent and/orreduce unacceptable loads from being applied to any part of aircraft400. These loads may be loads that may occur with respect to swing tailcargo door 416 for aircraft 400. The loads on swing tail cargo door 416may be placed on to the hinge and there through into other portions ofaircraft 416. These loads may occur during movement, such as, forexample, without limitation, opening and closing of swing tail cargodoor 416. These loads also may occur during other operations, such as,for example, without limitation, loading and/or unloading of cargo fromaircraft 400.

FIGS. 6-9 provide more detailed illustrations of vertical support system500 in FIG. 5. Turning now to FIG. 6, an illustration of components in avertical support system is depicted in accordance with an advantageousembodiment. In this example, vertical support system 506 is shown inmore detail in this perspective view of a portion of mobile tail supportapparatus 500. As depicted, vertical support system 506 includes bottomlift structure 600, middle lift structure 602, and upper lift structure604. Vertical support system 506 also includes balcony 606. Horizontalsupport system 508 may be mounted on upper lift structure 604 in theseexamples.

More detailed illustrations and descriptions of horizontal supportsystem 508 may be found below with respect to FIGS. 11 and 12. Verticalsupport system 506 also includes accumulator tank unit 608. Asillustrated, vertical support system 506 may provide smooth verticalextension with minimal resistance while maximizing horizontal stability.

Turning now to FIG. 7, an illustration of lift structures in verticalsupport system is depicted in accordance with an advantageousembodiment. In this example, rollers 700, 701, 702 and 703 are shown.These rollers may be secured between middle lift structure 602 and upperlift structure 604. Roller 704 is shown. Another roller similar toroller 704 may be present behind cover 705. Roller 704 and the rollerbehind cover 705 allow the chains routed over these rollers to freelyretract and extend in response to the lift structure mid sectionvertical movement. These rollers may rotate for a smoother extensionwith minimal resistance to the chain. The roller behind the cover 705may be the same roller that attaches to chain 804 in FIG. 8.

Also, two additional small rollers, like rollers 701 and 703, and twoadditional large rollers, like rollers 700 and 702, may be present belowthe rollers 704 and behind cover 705 as well as on opposite side.Smaller rollers, such as rollers 700 and 702, may provide for smoothvertical lift operations. These operations may occur with minimumclearance and resistance between them and the surface the rollers reactagainst with the tight lateral tolerances that may be required forsmooth operations.

These rollers may rotate for a smoother extension with minimalresistance. Rollers 700 and 702, as well as the ones hidden behind cover705 and roller 704 and on the opposite side may provide for smoothvertical lift operations to occur with minimum clearance and resistancebetween them and the surface they react against with the tight forwardand/or aft tolerances that may be required for smooth operations.

Additionally, these rollers behave as the smaller ones, like rollers 701and 703, mentioned above. Roller 704 and the roller hidden behind cover705 may react to loads that may be considerably larger in the forwardand/or aft direction. Although the particular configuration of rollers700, 701, 702, 703, and 704 may provide for purposes of depicting onemechanism, smoother extension of upper lift structure 604, other typesof mechanisms may be employed depending on the particularimplementation.

With reference now to FIG. 8, an illustration of lift mechanisms for avertical support system is depicted in accordance with an advantageousembodiment. In this example, lift cylinder 800, chain 802, and chain 804are examples of mechanisms that may be used to provide lifting force forvertical support system 506.

Lift cylinder 800 may be used to provide lift for middle lift structure602. Chain 802 and chain 804 may be used to provide lifting forces forupper lift structure 604, which is not shown in this view. Chain 802 maybe laid over roller 704, while chain 804 may be laid over another rollerthat is not shown. Further, post 806 may be used to provide maintenancesafety.

With reference next to FIG. 9, an illustration of a portion of avertical support system is depicted in accordance with an advantageousembodiment. In this example, the vertical load may be monitored usingload cell monitor 900. Load cell monitor 900 may be mounted at the fixedend of chain 804. Another load cell and chain also may be present on theopposite side at the fixed end of chain 802. Further, this example alsoillustrates more details of accumulator unit 902, which is a moredetailed example of accumulator unit 314 in FIG. 3.

Accumulator unit 902 includes tanks 904 and 906. These tanks may be usedto provide gas that may be fed or pumped into accumulator tank 908.Accumulator unit 902 may provide a shock absorber for vertical supportsystem 506. In these examples, pressure transducer 910 and pressuretransducer 911 attached to accumulator tank 908 may provide feedback asto the amount of pressure present within tanks 904 and 906 in theseexamples.

As depicted, accumulator tank 908 contains hydraulic fluid in a chamber(not shown) over a piston (not shown) pressured by a gas located in tank904 and tank 906. This gas may be, for example, without limitation,nitrogen or some other suitable gas. Accumulator unit 902 may provide alifting force with constant pressure and vertical compliance, in theseexamples. In other words, accumulator unit 902 may act as a shockabsorber. Accumulator unit 902 may react in response to vertical forcesor loads applied to vertical support system 506.

Accumulator unit 902 may allow vertical movement during the opening,loading and unloading operations, and closing of a swing tail cargo doorwithout requiring an operator to adjust the vertical force. Accumulatorunit 902 may provide a passive system to maximize protection of theaircraft against undesired vertical forces being applied to the swingtail cargo door. Accumulator unit 902 may move several inches within ashort period of time, without substantial changes in the interface loadwith swing tail cargo door 416.

Accumulator unit 902 may respond or react to vertical movement of swingtail cargo door 416 during opening, closing, and loading and unloadingof cargo from swing tail aircraft 400. In other words, accumulator unit902 provides a shock absorber or a passive spring support function.Valves may be present within accumulator unit 902 to regulate the flow,restrict lifting, and lowering based on operations being performed onthe swing tail cargo door.

In FIG. 10, an illustration of components used in providing lift forcesin a vertical support system is depicted in accordance with anadvantageous embodiment.

In these examples, mobile tail support apparatus 500 may include engine1000, hydraulic pump and reservoir tank 1002, chassis valves 1004, flowrate valve 1006, blocking valve 1008, accumulator piston unit 1010,manual blocking valves 1012, automatic blocking valves 1014, liftcylinder 1016, middle lift structure 1018, and upper lift structure1020.

The different components in this illustrative example may be implementedin mobile tail support apparatus 300 in FIG. 3 to provide lift forceswithin vertical support system 304 in FIG. 3. In this example, engine1000 may provide electrical power to run hydraulic pump and reservoirtank 1002. Engine 1000 may be the engine for mobile support base 510.

Chassis valves 1004 may provide hydraulic fluid for generating liftforces within vertical support system 506. Chassis valves 1004 may beoperated by an operator or user of mobile tail support apparatus 300 inthese examples. Chassis valves 1004 also may provide a return forhydraulic fluid to hydraulic pump and reservoir tank 1002.

Flow rate valve 1006 may control the rate at which hydraulic fluid flowsto and from chassis valve 1004 and blocking valve 1008. Flow rate valve1006 may provide for fast or full open flow for filling an accumulatortank with hydraulic fluid. When the tank has been filled, flow ratevalve 1006 may close partially or entirely at the working pressuredesired for the accumulator tank. Blocking valve 1008 may prevent theflow of hydraulic fluids to the tanks and the accumulator unit unlessthe operator is lifting or moving middle lift structure 1018.Accumulator piston unit 1010 may be operated to allow full movementwithin a working pressure range within the accumulator unit. Manualblocking valves 1012 may be typically open, but may be closed formaintenance purposes.

Automatic blocking valves 1014 may provide non-mobile protection forunexpected forces. These values may be activated by the swing tailcontrol system 310 when an imbalance or rapid change in pressure isdetected, such as a rapid unexpected change in hydraulic pressure. Liftcylinder 1016 may be powered by hydraulic fluid flowing from theaccumulator unit to provide lift to middle lift structure 1018. Upperlift structure 1020 may be raised and lowered by chains. In thisexample, the chains may be under tension with one end connected to thebottom lift structure, the other end connected to the upper liftstructure, and routed over rollers in the middle section such that whenthe middle section is raised by hydraulic cylinders, the chains may pullup the upper lift structure.

Turning now to FIG. 11, an illustration of a horizontal support systemcoupled to a swing tail cargo door is depicted in accordance with anadvantageous embodiment. In this example, horizontal support system 508in mobile tail support apparatus 500 may engage swing tail cargo door416 of aircraft 400 to move from position 1100 to position 1102 alongarc 1104. Arrow 1105 may indicate a forward direction for mobile tailsupport apparatus 500. This movement moves swing tail cargo door 416from position 1106 to position 1108 along hinge 1110. Rotationaltransducers may be located along hinge 1110 to provide an identificationof the position of swing tail cargo door 416. This information may betransmitted to mobile tail support apparatus 500.

In this example, mobile tail support apparatus 500 may be pointed in atangential direction as identified by arrow 1112. The tangentialdirection identified by arrow 1112 may be the direction that mobile tailsupport apparatus 500 travels when opening swingtail cargo door 416 in adrive mode. A radial direction may be identified by arrow 1114. Theradial direction may be a direction perpendicular to the tangentialdirection and towards hinge 1110.

Horizontal support system 508 may provide an ability to preventunacceptable loads from being introduced into hinge 1110 and/or swingtail cargo door 416 during operations in which swing tail cargo door 416may be repositioned or moved. These unacceptable loads may occur due toany number of reasons including from operating swing tail cargo door416, loading and unloading operations, or wind loading on swingtailcargo door 416 and/or aircraft 400.

Turning now to FIG. 12, an illustration of a horizontal support systemis depicted in accordance with an advantageous embodiment. In thisexample, horizontal support system 508 contains cross track slide system1200. Arrow 1201 may indicated a forward direction of mobile tailsupport apparatus 500, which may correspond to the direction of mobiletail support apparatus 500 in FIG. 11 as indicated by arrow 1105.

Cross track slide system 1200 may include radial slide rails 1202 and1204 on which radial platform 1206 may slide along the direction ofarrow 1208. In these examples, radial platform 1206 and the differentcomponents attached to radial platform 1206 may remain at a “constant”distance from the centerline 1230 to centerline through hinge 1110 atall times after attachment and until detachment operations may becompleted. The distance of mobile tail support apparatus 500 thecenterline though hinge 1110 of swing tail cargo door 416 may vary.

Radial slide rails 1202 and 1204 allow radial platform 1206 freedom ofmovement in a radial direction along the direction of arrow 1208. Thismovement may prevent unacceptable loads from being applied to the swingtail cargo door. In these examples, sensor 1211 may identify the radialdisplacement or location of radial platform 1206 with respect to mobiletail support apparatus 500 during operations.

Further, the removal of tangential preload may be provided duringdetachment operations of the swing tail cargo door using tangentialadjustment hand wheel 1220. This hand wheel and radial adjustment handwheel 1210 may be used to provide tangential and radial adjustment foralignment purposes during attachment operations.

In these examples, tangential platform 1212 may slide on tangentialslide rails 1214, 1216, and 1218 along the direction of arrow 1219.These rails may be mounted on radial platform 1206. These tangentialslide rails may be mounted on radial platform 1206. Tangential platform1212 may not have the freedom of movement during operation of mobiletail support apparatus 500. Instead, tangential platform 1212 may remainfixed in place in relation to the radial platform 1206 during mostoperations. Tangential platform 1212 may be moved for alignment anddetachment purposes using tangential hand wheel 1220.

In this example, ball fitting 1222 may be an example of a couplingmechanism, such as coupling mechanism 308 in FIG. 3. Ball fitting 1222may couple or engage the swing tail cargo door at a socket, such as forexample, without limitation, socket 504 in FIG. 5. Ball fitting 1222 maybe mounted on and fixed in place on tangential platform 1212. Ballfitting 1222 may be mounted permanently to tangential platform 1222.

Under normal operations, ball fitting 1222 may provide an upward forceinto socket 504. The upward force may be produced by hydraulic pressuregenerated by mobile tail support apparatus 500 and by resistance to thispressure from swing tail cargo door 416. Lock plate 1224 may provide anadditional mechanism to ensure that ball fitting 1222 remains engaged orcoupled to socket 504 of swing tail cargo door 416 to prevent freemovement of the swing tail cargo door relative to ball fitting 1222. Anexample of a situation in which the coupling of ball fitting 1222 mayremain in place with swing tail cargo door 416 may be a hydraulicfailure in the mobile tail support apparatus.

Chassis angle index pin 1226 may be attached to angular measurementbracket 1228. Angular measurement bracket 1228 may rotate aroundcenterline 1230 for ball fitting 1222. Chassis angle index pin 1226 maybe used to identify an angular relationship of the mobile tail supportapparatus with respect to swing tail cargo door 416 around hinge 1110.

The ability of horizontal support system 508 to move along radialdirection 1208 may prevent undesired radial loads from being introducedonto swing tail cargo door 416 and/or the hinge of the swing tail cargodoor from mobile tail support apparatus 500. Chassis angle rotary sensor1232 may identify the rotation of swing tail cargo door 416 about ballfitting 1222 with respect to mobile tail support apparatus 500.

In these examples, mobile tail support apparatus 500 may move in aradial direction a predetermined distance from the centerline of theball fitting 1222 along radial direction 1208. This predetermineddistance may provide a range of movement to allow the mobile tailsupport apparatus 500 to be driven along an arc during opening andclosing operations without imposing undesired radial loads on swing tailcargo door 416 and/or hinge 1110. For example, without limitation, ifthe mobile tail support apparatus 500 drives a few inches off an idealarc path, ball fitting 1222 may move, in relation to the mobile tailssupport apparatus 500 in a radial direction an equivalent amount whilemaintaining interface loads in the vertical and tangential directions.

Horizontal support system 508 may provide a tangential compliancefeature to align ball fitting 1222 with socket 504 on swing tail cargodoor 416 when coupling ball fitting 1222 to swing tail cargo door 416.This feature also allows for removal of tangential preload duringdetachment operations.

The angular value, the radial displacement from the mobile tail supportapparatus 500 centerline to the centerline of the ball fitting, and thecurrent steering angle of the wheels for the mobile tail supportapparatus may be used to determine guidance or changes in movement ofthe mobile tail support apparatus 500 to minimize or reduce undesiredforces on swing tail cargo door 416 during repositioning or movement ofswing tail cargo door 416.

The angular value may be, for example, without limitation, the angle ofmobile tail support apparatus 500 relative to swing tail cargo door 416.The radial displacement may be a change in the distance of an attachmentpoint of mobile tail support apparatus 500 from an axis of rotation ofswing tail cargo door 416. The axis of rotation may be, for example,without limitation, hinge 1110.

Turning now to FIG. 13, an illustration of a swing tail control systemis depicted in accordance with an advantageous embodiment. In thisexample, swing tail control system 1300 is an example of oneimplementation Swing tail control system 310 in FIG. 3. Swing tailcontrol system 1300 may include data processing system 1302 whichreceives input from sensors. Control process 1303 takes the form of acomputer program that executes on data processing system 1302 to managemovement of mobile tail support apparatus 300 in response to receivinginput from the sensors.

These sensors include, for example, without limitation, speed sensor1304, steering angle sensor 1306, chassis angle sensor 1308, verticalload sensors 1310, tail opening angle sensors 1312, radial slideposition sensor 1314, over travel switches 1316, gear selector positionsensor 1318, and tangential sensor 1319. In response to these inputs,control process 1303 may generate guidance in the form of outputs tolift vertical load isolation 1320, steering guidance display 1322, andbrake valve 1324.

Speed sensor 1304 may provide information about the speed at which themobile tail support apparatus may be traveling. Steering angle sensor1306 may identify the angle at which a wheel is turned on the mobiletail support apparatus. Chassis angle sensor 1308 may detect the angleof a centerline of the chassis with respect to a line for a radialdistance to the hinge of the swing tail cargo door. More specifically,chassis angle sensor 1314 may be an example of angle sensor 332 in FIG.3. This sensor may be, for example, without limitation, chassis anglerotary sensor 1232 in FIG. 12 or some other suitable sensor.

Vertical load sensors 1310 may provide information about the loading onthe vertical support system. Vertical load sensors 1310 may be examplesof vertical load sensor 326 in FIG. 3. More specifically, vertical loadsensors 1310 may be, for example, without limitation, implemented usingload cell sensor 900. In these examples, a load cell sensor may be usedwith each lift chain in FIG. 9 or some other suitable sensor. Tailopening angle sensors 1312 may provide information about the position ofswing tail cargo door 416 with respect to the rest of swing tailaircraft 400. These sensors may be located along or in hinge 1110 of theswing tail cargo door 416.

Radial slide position sensor 1314 may provide information about theradial displacement of mobile tail support apparatus 500 with respect toan ideal arc along which mobile tail support apparatus 500 may travel.An ideal arc corresponds to the path the ball fitting centerline 1230makes in a horizontal plane as swingtail rotates about hinge 1110. Thisradial displacement may be a selected distance plus or minus a valuewith respect to the desired radial distance from hinge 1110 of swingtail cargo door 416. Radial slide position sensor 1314 may beimplemented using radial travel linear sensor 1211 in FIG. 12.

Over travel switches 1316, located near the ends of radial sensor 1211,may provide an indication of radial travel beyond an allowed and/ordesired distance. Gear selector position sensor 1318 may provide anidentification of the direction traveled by mobile tail supportapparatus 500.

Tangential sensor 1319 may provide information about the amount ofrotational force that may be imparted on swing tail aircraft 400 at ballfitting 1222. Tangential sensor 1319 sensor may be used to allow theoperator to know when the preload is at a low enough level to safelydecouple mobile tail support apparatus 500 from swing tail aircraft 400.Tangential sensor 1319 also may be used to automatically engage brakesystem 339 if loads on swing tail aircraft 400 exceed preset parametersin either the forward or reverse directions for movement of mobile tailsupport apparatus 500.

Vertical load isolation 1320 may be an output that provides anadjustment to the amount of pressure or position of the vertical supportsystem. Vertical load isolation 1320 may provide information or signalsto control various valves and pumps for the vertical support system. Forexample, to increase the vertical load the blocking valve 1008 may beopened and hydraulic pump 1002 may be run to increase hydraulic pressurein the vertical support system 304.

Steering guidance display 1322 may provide steering signals to anoperator of the mobile tail support apparatus. In other words, thesteering signals may provide steering guidance to an operator on adisplay. These steering signals may provide an indication of the changesin the direction of travel for the mobile tail support apparatus thatmay be needed to minimize or reduce undesirable forces on the swing tailcargo door.

Brake valve 1324 may be controlled by data processing system 1302 tohalt movement of mobile tail support apparatus 500. Halting of mobiletail support apparatus 500 may occur if mobile tail support apparatus500 has traveled beyond some distance or has caused an undesirable loadto occur on swing tail cargo door 416.

Turning now to FIG. 14, a diagram of a data processing system isdepicted in accordance with an advantageous embodiment. Data processingsystem 1400 is an example of one implementation for data processingsystem 1302 in FIG. 13. In this illustrative example, data processingsystem 1400 includes communications fabric 1402, which providescommunications between processor unit 1404, memory 1406, persistentstorage 1408, communications unit 1410, input/output (I/O) unit 1412,and display 1414.

Processor unit 1404 serves to execute instructions for software that maybe loaded into memory 1406. Processor unit 1404 may be a set of one ormore processors or may be a multi-processor core, depending on theparticular implementation. Further, processor unit 1404 may beimplemented using one or more heterogeneous processor systems in which amain processor may be present with secondary processors on a singlechip. As another illustrative example, processor unit 1404 may be asymmetric multi-processor system containing multiple processors of thesame type.

Memory 1406, in these examples, may be, for example, a random accessmemory or any other suitable volatile or non-volatile storage device.Persistent storage 1408 may take various forms depending on theparticular implementation. For example, persistent storage 1408 maycontain one or more components or devices. For example, persistentstorage 1408 may be a hard drive, a flash memory, a rewritable opticaldisk, a rewritable magnetic tape, or some combination of the above. Themedia used by persistent storage 1408 also may be removable. Forexample, a removable hard drive may be used for persistent storage 1408.

Communications unit 1410, in these examples, provides for communicationswith other data processing systems or devices. In these examples,communications unit 1410 may be for example, without limitation, anetwork interface card or some other suitable device. Communicationsunit 1410 may provide communications through the use of either or bothphysical and wireless communications links.

Input/output unit 1412 allows for input and output of data with otherdevices that may be connected to data processing system 1400. Forexample, input/output unit 1412 may provide a connection for user inputthrough a keyboard and mouse or other suitable means. Further,input/output unit 1412 may send output to a printer or other suitableoutput device. Display 1414 provides a mechanism to display informationto a user.

Instructions for the operating system and applications or programs maybe located on persistent storage 1408. These instructions may be loadedinto memory 1406 for execution by processor unit 1404. The processes ofthe different embodiments may be performed by processor unit 1404 usingcomputer implemented instructions, which may be located in a memory,such as memory 1406. These instructions may be referred to as programcode, computer usable program code, or computer readable program codethat may be read and executed by a processor in processor unit 1404. Theprogram code in the different embodiments may be embodied on differentphysical or tangible computer readable media, such as memory 1406 orpersistent storage 1408.

Program code 1416 may be located in a functional form on computerreadable media 1418 that may be selectively removable and may be loadedonto or transferred to data processing system 1400 for execution byprocessor unit 1404. Program code 1416 and computer readable media 1418form computer program product 1420 in these examples. In one example,computer readable media 1418 may be in a tangible form, such as, forexample, without limitation an optical disc, magnetic disc, or someother suitable media that may be inserted or placed into a drive orother device that may be part of persistent storage 1408 for transferonto a storage device.

The storage device may be, for example, without limitation, a hard drivethat is part of persistent storage 1408 or some other suitable device.In a tangible form, computer readable media 1418 also may take the formof a persistent storage, such as without limitation a hard drive, athumb drive, or a flash memory that may be connected to data processingsystem 1400. The tangible form of computer readable media 1418 may alsobe referred to as computer recordable storage media. In some instances,computer readable media 1418 may not be removable.

Alternatively, program code 1416 may be transferred to data processingsystem 1400 from computer readable media 1418 through a communicationslink to communications unit 1410 and/or through a connection toinput/output unit 1412. The communications link and/or the connectionmay be physical or wireless in the illustrative examples. The computerreadable media also may take the form of non-tangible media, such ascommunications links or wireless transmissions containing the programcode.

The different components illustrated for data processing system 1400 arenot meant to provide architectural limitations to the manner in whichdifferent embodiments may be implemented. The different illustrativeembodiments may be implemented in a data processing system includingcomponents in addition to or in place of those illustrated for dataprocessing system 1400. Other components shown in FIG. 14 can be variedfrom the illustrative examples shown.

As one example, a storage device in data processing system 1400 may beany hardware apparatus that stores data. Memory 1406, persistent storage1408 and computer readable media 1418 may be non-limiting examples ofstorage devices in a tangible form.

In another example, a bus system may be used to implement communicationsfabric 1402 and may be comprised of one or more buses, such as a systembus or an input/output bus. Of course, the bus system may be implementedusing any suitable type of architecture that provides for a transfer ofdata between different components or devices attached to the bus system.Additionally, a communications unit may include one or more devices usedto transmit and receive data, such as, for example, without limitation,a modem, a network adapter, or some other suitable device. Further, amemory may be, for example, without limitation, memory 1406, a cachesuch as found in an interface and memory controller hub that may bepresent in communications fabric 1402, or some other suitable device.

With reference next to FIG. 15, an illustration of geometries andparameters for controlling a mobile tail support apparatus is depictedin accordance with an advantageous embodiment. In this example, tirelocations 1500, 1502, 1504, and 1506 may identify the locations of tiresfor mobile tail support apparatus 500. Attachment point 1508check/verify identifies the location at which ball fitting 1222 couplesto swing tail cargo door 416.

Centerline 1509 may identify the centerline of the mobile support basefor the mobile support apparatus. Steering angle α 1511 may identify theangle of the steering wheel for the mobile support apparatus. This anglemay be shown as an actual angle and/or a theoretical angle in thedifferent embodiments. The actual angle at which tire 1504 may be turnedwith respect to centerline 1508 may be shown for steering angle α 1511.The theoretical angle α may be the angle at which tire 1504 should beturned relative to centerline 1508. In these examples, wheel 1506 may berotated at same angle α as wheel 1504.

Wheel base (WB) 1510 may be the wheel base of the mobile tail support500. Wheel base 1510 may identify the distance between the axle forwheels 1500 and 1502 and wheels 1504 and 1506. Coupling radius 1512 maybe the distance from hinge 1110 and attachment point 1508. Radius a 1514may be the distance from hinge 1110 to the front axle of mobile tailsupport apparatus 500 along line 1516 for wheels 1500 and 1502. In theseexamples, this radius may be calculated as follows:

√{square root over (r²−LC²)}

Distance LC 1518 may be the distance along centerline 1508 from the axleto the center of the ball fitting. Angle β 1520 may be the angle of thechassis for the mobile tail support apparatus relative to the hingeradius as identified by coupling radius r 1512. The displacement ofhorizontal support system 508 for ball fitting 1222 may be the radialdisplacement d, in these examples.

In the depicted examples, wheel base 1510 may be, for example, withoutlimitation, around 225 inches. Coupling radius 1512 may be, for example,without limitation, around 410 inches. Distance LC 1518 may be, forexample, without limitation, 10.5 inches.

In these examples, the theoretical steering angle α 1511 is needed toremain within the desired arc of travel may be calculated as follows:

$\alpha = {\tan^{- 1}\left( \frac{WB}{a} \right)}$

In the advantageous embodiments, two variables may be present in swingtail control system 310. These variables may be, for example, withoutlimitation, the radial displacement d and chassis angle β 1520.

Changes in the radial displacement may change the value of radius a1514. This change may affect theoretical steering angles needed to guidemobile tail support apparatus 500 along the desired arc. Changes inchassis angle β 1520 may occur directly proportional to steering angle α1511 as calculated above.

In the different advantageous embodiments, any displacement on theradial slide rail as identified by radial displacement d may make achange in radius a 1514 as follows:

a _(c)=√{square root over (r ² −LC ²)}+(K1*d)

a_(c) may be the corrected radius, d may be the radial displacement, andK1 may be a gain factor for radial displacement.

In the different advantageous embodiments, since the chassis angle mayhave a direct relationship with the steering angle, a referencedsteering angle may be selected as follows:

$\alpha_{F} = {{\tan^{- 1}\left( \frac{WB}{a_{c}} \right)} + \left( {K\; 2*\beta} \right)}$$\alpha_{R} = {{\tan^{- 1}\left( \frac{WB}{a_{c}} \right)} - \left( {K\; 2*\beta} \right)}$

α_(F) may be the steering reference angle for the forward motion, α_(R)may be the reference steering angle for the reverse motion, and K2 maybe a gain factor for the chassis angle.

In the different advantageous embodiments, the constants for gains K1and K2 may be identified through various trials and experiments toobtain empirical data. These gains may be selected to provide a leastradial error while providing adequate stability. Changes to these valuesmay change because of the changes in the tires or weight of mobile tailsupport apparatus 500. The referenced steering angles, α_(F) and α_(R),may be continuously computed for forward and reverse movements of mobiletail support apparatus 500 based on the position of the gear shift forthe mobile tail support apparatus 500. This angle may then be comparedto the actual steering angle of the chassis and the difference may begraphically displayed.

In this manner, an operator may provide guidance to correct or alter thesteering of mobile tail support apparatus 500 to minimize the differencethat may be present. Alternatively, an automatic steering system may beemployed to automatically change the direction of mobile tail supportapparatus 500.

In addition to monitoring the movement of mobile tail support apparatus500 and providing guidance, data processing system 1302 also may monitorthe angle of swing tail cargo door 416 from sensors in hinge 1110 andthe radial displacement of the mobile tail support apparatus 500 fromhinge 1110 to determine if or whether movement of the mobile tailsupport apparatus 500 should stop. A threshold value and/or distance maybe used to cause sending of a signal to brake system 339 of mobile tailsupport apparatus 500 to stop mobile tail support apparatus 500 in orderto prevent movement of mobile tail support apparatus 500 outside of someboundary or distance.

Once applied, the brake system 339 may be overridden by supplying apassword to control system 310 in these examples. The activation of thebrake system 339 may be initiated through a solenoid driven hydraulicvalve that supplies brake pressure, bypassing the normal input generatedby an operator. Further, vertical load sensors and lift truck speedsensors also may be used to activate brake system 339 if any of theparameters monitored by the sensors move outside of some threshold.

With reference now to FIG. 16, an illustration of a steering guidancedisplay is depicted in accordance with an advantageous embodiment. Inthis example, display 1601 may be an example of a display presented toan operator of mobile tail support apparatus 500 to guide the operatorin steering and controlling movement of mobile tail support apparatus500. Display 1601 may be an example of steering guidance display 1322 inFIG. 13. Buttons 1600, 1602, and 1604 may be touch screen buttons thatmay provide information, such as, for example, without limitation,parameter history, system status, by-pass override controls and/or othersuitable information.

Main button 1606 may return display 1322 to the main display screen aspresented in this example. Button 1608 may be used to enable and disablethe lower lift structure in the mobile tail support apparatus 500.Button 1610 may allow a user to toggle between the main screen as shownand a screen displaying information about hydraulics, radial travel, arcmovement of the mobile tail support apparatus 500 and/or other suitableinformation. Aircraft load feedback indicator 1612 displays the netweight of swing tail cargo door 416. Tangential load feedback indicator1614, may identify the tangential load on the swing tail cargo door.

Graphical bar 1616 identifies the current speed of mobile tail supportapparatus 500. Graphical bar 1618 identifies the brake pressure beingapplied to mobile tail support apparatus 500.

Radial displacement indicator 1620 may identify the radial displacementof mobile tail support apparatus 500 from the nominal value of couplingradius 1512 when engaged to swing tail cargo door 416. In its currentposition, radial displacement indicator 1620 may indicate that mobiletail support apparatus 500 is within the radial displacement. Movementof this indicator to the left or right may indicate that mobile tailsupport apparatus 500 has shifted radially with respect to thehorizontal support system because of movement of mobile tail supportapparatus 500 away from the desired ideal arc value of coupling radius1512.

Gear indicator 1622 may indicate whether mobile tail support apparatus500 may be in reverse, neutral, or forward. Angle indicator 1624identifies the angle of mobile support base 302 with respect to thechassis angle of swing tail aircraft 400.

Theoretical steering angle 1626 identifies the desired steering anglefor mobile tail support apparatus 500. Actual steering angle 1628identifies the actual steering angle of mobile tail support apparatus500.

Message line display 1630 may be used to display messages to anoperator. Swing tail opening angle 1632 identifies the angle of swingtail aircraft 400 with respect to the rest of the aircraft. Nitrogenindicator 1634 identifies the amount of nitrogen that may be present inthe different nitrogen tanks in mobile tail support apparatus 500.By-pass mode indicator 1636 indicates whether mobile tail supportapparatus 500 may be operating in a by-pass mode.

A by-pass mode may be activated when by-pass over ride functionsassociated with button 1604 are used to turn off the feedback of one ormore sensors used as an input for data processing system 1302. Forexample, if radial slide position sensor 1314 is by-passed, then dataprocessing system 1302 may not engage brake valve 1324 even if theradial slide position sensor is activated, thereby allowing operation tocorrect the condition that caused mobile tail support apparatus 500 tocease movement.

Transport mode indicator 1638 may be used to indicate that mobile tailsupport apparatus 500 may be operated at high speeds such as when themobile tail support apparatus 500 is moving from it's storage locationto and/or from swing tail aircraft 400. Chassis angle rotary sensor homeindicator 1640 identifies that controls 1303 have received signals fromrotary sensor 1232 to lock in accurate angle readings. Accumulatorpiston indicator 1642 may be used to identify the position of the pistonin the accumulator unit. Cell feedback indicators 1644 and 1646 may beused to provide a graphical representation of the load or pressuredisplayed in aircraft load feedback indicator 1612 and hydraulicpressure reading 1650.

Cylinder stroke feedback indicator 1648 may be used to identify theextension or height of vertical support system 506. Hydraulic pressurereading 1650 may provide identification of the hydraulic pressure withinmobile tail support apparatus 500. Change filter indicator 1652 mayindicate when a filter for the hydraulic system should be changed. Tiltenable button 1654 may allow vertical support system 506 to tilt or beangled rearward or forward with respect to mobile tail support apparatus500. In these examples, the tilt may be, for example, withoutlimitation, around two degrees, zero degrees, and/or or some othersuitable angle.

Display 1601 is presented as one example of a display that may be usedto provide guidance in operating mobile tail support apparatus 500. Thisparticular example is not meant to limit the manner in which guidancefor managing movement of mobile tail support apparatus 500 may bepresented.

In other implementations, for example, without limitation, a path or arcwith a mobile tail support apparatus 500 or other suitable informationmay be displayed. In this type of presentation, the angle of the wheelsmay be displayed with the actual position of the wheels and the desiredposition of the wheels. As the user changes the position of the wheelsthrough the steering wheel, the actual position displayed may change.When the angle for the actual steering of the wheels matches thetheoretical angle, then the actual wheels may overlap the theoreticalwheels in the display. Further, other information, such as, for example,without limitation, as the values for the actual and theoreticalsteering angles also may be presented.

Turning now to FIG. 17, a flowchart of a process for managing movementof a mobile tail support apparatus is depicted in accordance with anadvantageous embodiment. This flowchart is a high level flowchart of aprocess that may be implemented in a mobile tail support apparatus 500,such as mobile tail support apparatus 300 in FIG. 3. In particular, thedifferent processes may be implemented in a data processing system, suchas data processing system 1400 in FIG. 14 as part of swing tail controlsystem 310 in FIG. 3.

The process begins with a known radial displacement value for the mobiletail support apparatus 500 from swing tail cargo door 416 (operation1700). This radius may be coupling radius 1512 which may be a distancefrom a point at which the ball fitting 1222 on mobile tail supportapparatus 500 may be coupled to swing tail cargo door 416 to hinge 1110of swing tail cargo door 416. Thereafter, an angle of mobile tailsupport apparatus 500 relative to swing tail cargo door 416 may bereceived with mobile support tail apparatus 500 coupled to swing tailcargo door 416 (operation 1702).

Thereafter, the process may selectively change movement of the mobiletail support apparatus 500 based on the received radial displacementfrom the nominal coupling radius and the received angle (operation 1704)with the process terminating thereafter.

The selective change in movement may be to provide steering signals tochange the direction at which mobile tail support apparatus 500 may betraveling. The selective change also may be to halt mobile tail supportapparatus 500 by applying braking if mobile tail support apparatus 500has exceeded some threshold radial displacement distance from thenominal/desired value for the radial displacement. This distance may bethe amount of travel that may occur along horizontal support system 508.In particular, if radial platform 1206 moves along radial slide rails1202 and 1204 in relation to centerline 1509 of mobile tail supportapparatus 500 more than a predetermined distance, brake system 339 maybe applied to mobile tail support apparatus 500 to prevent undesiredforces from being applied to swing tail cargo door 416.

Turning now to FIG. 18, a flowchart of a process for monitoring loads ona mobile tail support apparatus is depicted in accordance with anadvantageous embodiment. The process in FIG. 18 may be implemented in aprocess, such as data processing system 1302 in FIG. 13.

The process begins by monitoring information from different load sensors(operation 1800). Thereafter, a determination may be made as to whethera load value may be beyond a first threshold (operation 1802). If theload value is not beyond the first threshold for the different loadsensors, the process returns to operation 1800. Otherwise, adetermination may be made as to whether the load value may be beyond asecond threshold (operation 1804).

If the load value is not beyond a second threshold, hydraulic pressuremay be adjusted to counter or react to the load (operation 1806) withthe process then returning to operation 1800.

If the load value is beyond a second threshold, the process may thenhalt movement of the mobile tail support apparatus 500 (operation 1808)with the process terminating thereafter.

The flowcharts and block diagrams in the different depicted embodimentsillustrate the architecture, functionality, and operation of somepossible implementations of apparatus, methods and computer programproducts. In this regard, each block in the flowchart or block diagramsmay represent a module, segment, or portion of computer usable orreadable program code, which comprises one or more executableinstructions for implementing the specified function or functions. Insome alternative implementations, the function or functions noted in theblock may occur out of the order noted in the figures. For example, insome cases, two blocks shown in succession may be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved.

The description of the different advantageous embodiments has beenpresented for purposes of illustration and description, and is notintended to be exhaustive or limited to the embodiments in the formdisclosed. Many modifications and variations will be apparent to thoseof ordinary skill in the art. Further, the different advantageousembodiments may provide different advantages as compared to otheradvantageous embodiments. The embodiment or embodiments selected arechosen and described in order to best explain the principles of theembodiments, the practical application, and to enable others of ordinaryskill in the art to understand the disclosure for various embodimentswith various modifications as are suited to the particular usecontemplated.

1. A mobile tail support control system for controlling movement of amobile tail support apparatus, the control system comprising: a dataprocessing system; an output device coupled to the data processingsystem capable of generating signals for managing movement of a mobiletail support apparatus; a set of load sensors coupled to the dataprocessing system and capable of detecting a set of loads associatedwith a swing tail cargo door, wherein the set of load sensors comprise afirst load sensor capable of detecting a tangential load of the swingtail cargo door and a second load sensor capable of detecting a verticalload of the swing tail cargo door; a set of position sensors coupled tothe data processing system and capable of detecting a position of themobile tail support apparatus relative to the swing tail cargo door,wherein the set of position sensors comprise a first position sensorcapable of detecting an angle of the mobile tail support apparatusrelative to the swing tail cargo door when the mobile tail supportapparatus is coupled to the swing tail cargo door, a second positionsensor capable of detecting a radial displacement from a fixed distancefrom a centerline of a for the swing tail cargo door to a centerline fora ball fitting of the mobile tail support apparatus relative to theswing tail cargo door, and a third position sensor capable of detectinga steering angle of a wheel on the mobile tail support apparatus; and acomputer program product executing on the data processing system iscapable of receiving information from the set of load sensors and theset of position sensors and is capable of generating signals to managethe mobile tail support apparatus, wherein in executing the computerprogram product, the data processing system generates a signal to haltthe movement of the mobile tail support apparatus if the radial travelexceeds a threshold distance and the data processing system generates aset of steering signals based on the angle of the mobile tail supportapparatus relative to the swing tail cargo door and the radial travel inwhich set of steering signals are displayed to an operator of the mobiletail support apparatus or automatically control a direction of travel ofthe mobile tail support apparatus.
 2. A computer implemented method forguiding movement of a mobile tail support apparatus, the computerimplemented method comprising: receiving radial displacement from acoupling radius of the mobile tail support apparatus from a swing tailcargo door to form a received radial displacement; receiving an angle ofthe mobile tail support apparatus relative to the swing tail cargo doorwhen the mobile tail support apparatus is coupled to the swing tailcargo door to form a received angle; and selectively changing themovement of the mobile tail support apparatus based on the receivedradial displacement and the received angle comprising: determiningwhether the movement of the mobile tail support apparatus causes anundesired load on the swing tail cargo door during opening and closingoperations; and responsive to a determination that the mobile tailsupport apparatus require steering guidance, providing guidance to theoperator display device by displaying a desired direction of themovement for the mobile tail support apparatus on a display device,sending steering signals to a steering unit to change a desireddirection of the movement for the mobile tail support apparatus, orstopping the movement of the mobile tail support apparatus.
 3. A mobiletail support control system comprising: a data processing system; anoutput device coupled to the data processing system capable ofgenerating signals for managing movement of a mobile tail supportapparatus; a set of load sensors coupled to the data processing systemand capable of detecting a set of loads associated with a swing tailcargo door; a set of position sensors coupled to the data processingsystem and capable of detecting a position of the mobile tail supportapparatus relative to the swing tail cargo door; and a computer programproduct executing on the data processing system is capable of receivinginformation from the set of load sensors and the set of position sensorsand is capable of generating signals to manage the mobile tail supportapparatus.
 4. The mobile tail support control system of claim 3, whereinthe set of load sensors comprises: a first load sensor capable ofdetecting a tangential load of the swing tail cargo door.
 5. The mobiletail support control system of claim 4, wherein the set of load sensorsfurther comprises: a second load sensor capable of detecting a verticalload of the swing tail cargo door.
 6. The mobile tail support controlsystem of claim 3, wherein the set of position sensors comprises: afirst position sensor capable of detecting an angle of the mobile tailsupport apparatus relative to the swing tail cargo door when the mobiletail support apparatus is coupled to the swing tail cargo door; and asecond position sensor capable of detecting a radial displacement from afixed distance from a centerline of a for the swing tail cargo door to acenterline for a ball fitting of the mobile tail support apparatusrelative to the swing tail cargo door.
 7. The mobile tail supportcontrol system of claim 3, wherein the set of position sensors furthercomprises: a third position sensor capable of detecting a steering angleof a wheel on the mobile tail support apparatus.
 8. The mobile tailsupport control system of claim 6, wherein the angle of the mobile tailsupport apparatus relative to the swing tail cargo door when the mobiletail support apparatus is an angle of a centerline of the mobile tailsupport apparatus relative to a hinge of the swing tail cargo door. 9.The mobile tail support control system of claim 6, wherein the radialtravel of the swing tail cargo door relative to the mobile tail supportapparatus is a distance of the coupling mechanism from a hinge of theswing tail cargo door.
 10. The mobile tail support control system ofclaim 6, wherein in executing the computer program product, the dataprocessing system generates a signal to halt the movement of the mobiletail support apparatus if the radial travel exceeds a thresholddistance.
 11. The mobile tail support control system of claim 10,wherein the signal causes at least one brake in the mobile tail supportapparatus to engage.
 12. The mobile tail support control system of claim6, wherein in executing the computer program product, the dataprocessing system generates a set of steering signals based on the angleof the mobile tail support apparatus relative to the swing tail cargodoor and the radial travel.
 13. The mobile tail support control systemof claim 12, wherein the set of steering signals are displayed to anoperator of the mobile tail support apparatus.
 14. The mobile tailsupport control system of claim 12, wherein the set of steering signalsautomatically control a direction of travel of the mobile tail supportapparatus.
 15. The mobile tail support control system of claim 12,wherein the set of steering signals minimize undesired loads on theswing tail cargo door.
 16. The mobile tail support control system ofclaim 3, wherein the data processing system comprises a programmablelogic controller.
 17. A computer implemented method for guiding movementof a mobile tail support apparatus, the computer implemented methodcomprising: receiving radial displacement from a coupling radius of themobile tail support apparatus from a swing tail cargo door to form areceived radial displacement; receiving an angle of the mobile tailsupport apparatus relative to the swing tail cargo door when the mobiletail support apparatus is coupled to the swing tail cargo door to form areceived angle; and selectively changing the movement of the mobile tailsupport apparatus based on the received radial displacement and thereceived angle.
 18. The computer implemented method of claim 17, whereinthe selectively changing step comprises: determining whether themovement of the mobile tail support apparatus requires steering guidanceto correct movement of the swing tail mobile apparatus; and responsiveto a determination that the mobile tail support apparatus requiresteering guidance, providing guidance to the operator display device.19. The computer implemented method of claim 18, wherein the determiningstep comprises: determining whether the movement of the mobile tailsupport apparatus causes an undesired load on the swing tail cargo doorduring opening and closing operations.
 20. The computer implementedmethod of claim 17, wherein the selectively changing step comprises:displaying a desired direction of the movement for the mobile tailsupport apparatus on a display device.
 21. The computer implementedmethod of claim 17, wherein the selectively changing step comprises:sending steering signals to a steering unit to change a desireddirection of the movement for the mobile tail support apparatus.
 22. Thecomputer implemented method of claim 17, wherein the selectivelychanging step comprises: stopping the movement of the mobile tailsupport apparatus.
 23. A computer program product for guiding movementof a mobile tail support apparatus, the computer program productcomprising: a computer readable media; program code, stored on thecomputer readable media, for receiving a radial displacement of themobile tail support apparatus from a swing tail cargo door to form areceived radial displacement; program code, stored on the computerreadable media, for receiving an angle of the mobile tail supportapparatus relative to the swing tail cargo door when the mobile tailsupport apparatus is coupled to the swing tail cargo door to form areceived angle; and program code, stored on the computer readable media,for selectively changing the movement of the mobile tail supportapparatus based on the received radial displacement and the receivedangle.
 24. The computer program product of claim 23, wherein the programcode, stored on the computer readable media, for selectively changingthe movement of the mobile tail support apparatus based on the receivedradial displacement and the received angle comprises: program code,stored on the computer readable media, for determining whether themovement of the mobile tail support apparatus causes an undesired loadon the swing tail cargo door; and program code, stored on the computerreadable media, for identifying a change in the movement needed toreduce the undesired load on the swing tail cargo door.
 25. The computerprogram product of claim 23, wherein the program code, stored on thecomputer readable media, for selectively changing the movement of themobile tail support apparatus based on the received radial displacementand the received angle comprises: program code, stored on the computerreadable media, for displaying a desired direction of the movement forthe mobile tail support apparatus on a display device.